Droplet actuators are used to conduct a wide variety of droplet operations. A droplet actuator typically includes two substrates separated by a gap. The substrates include electrodes for conducting droplet operations. The gap between the substrates is typically filled with a filler fluid that is immiscible with the fluid that is to be subjected to droplet operations. Droplet operations are controlled by electrodes associated with one or both of the substrates. In some applications, one or more bubbles (e.g., gaseous bubbles) may be introduced into a droplet actuator. A bubble can be transported, divided and otherwise manipulated using an actuated fluid (i.e., droplet). The manipulation of a bubble in a droplet actuator can provide additional functionalities to enhance droplet operations. There is a need for efficient methods for generating bubbles and for using bubbles in a droplet actuator.